function [f,curve] = adcurve5(x,indvar,target)
dd = [x(1) x(2) ] ;
curve = (dd(1)+(1-dd(1)).*exp(-dd(2).*(indvar')));
f = sum((100.*(target-(dd(1)+(1-dd(1)).*exp(-dd(2).*(indvar'))))./target).^2,'omitnan') ;